Bag bottom shaping device



July 5, 1955 F. GRAMEGNA BAG BOTTOM SHAPING DEVICE 7 Sheets-Sheet l Filed July 1l, 1952 July 5, 1955 F. GRAMEGN-A 2,712,275

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July 5, 1955 F. GRAMEGNA BAG BOTTOM sHAPING DEVICE.

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United States Patent O BAG BOTTOM SHAPING DEVICE Franco Gramegna, Milan, Italy, assignor to St. Regis Paper Company, New York, N. Y., a corporation of New York Application July 11, 1952, Serial No. 298,316 Claims. (Cl. 93-28) This invention relates to bag bottom forming apparatus, and more particularly to apparatus for forming side and corner aps thereon preparatory to the final forming of the bag bottom.

This invention includes improvements of certain of the elements of the bag bottom forming apparatus disclosed in my copending United States patent application Serial No. 189,271, filed October 9, 1950, now Patent No. 2,641,167, for Bag Bottom Forming Device. Such new elements can be employed in a device now in use in the United States of America.

One of the principal objects of this invention is to achieve a substantial increase in output of bottomed bag tubes by novel and simple means.

Apparatus disclosed in my aforementioned copending patent application has been successful in automatically opening the extremities of bag tubes and thereafter forming the side and corner flaps, such apparatus acting upon bag tubes of many types, including both multi-ply and single ply varieties which may be of either stiff kraft paper or paper of the less stit type. However, such apparatus described in my copending application has not fulfilled all of the desired results with respect to the shaping of tube ends in the relatively smaller sizes of bag tubes because of the relatively smaller aperture available for the insertion of the spreaderunit thereof. That is, the spreader unit employed in said copending application has a minimum practical size and hence a minimum practical dimension between the opposed points of its spreader tongues and also across the unit perpendicular thereto. It has not been found feasible to form the ends of bag tubes which do not easily admit such spreader unit because of the reduction in speed of the apparatus and because of the substantial percentageof rejects. Furthermore, certain types of bag tubes have the ends thereof stepped somewhat in the manner of roof shingles thereby presenting a plurality of staggered plies of paper at the outer surfaces of the tube end. It has been a practice in the past to open preliminarily such tube ends by means ot' opposed separable suction devices. I have found that such suction devices, when acting upon the ends of such stepped end bag tubes, frequently do not obtain a positive hold upon the stepped surfaces because of the stepped nature thereof and consequently frequently do not open the tube end to as wide an extent as is necessary for the insertion of the relatively large spreader unit of my aforementioned patent application.

One of the objects of the present invention is to overcome the above diiculties or to reduce same to insignificance. l

The invention in one aspect thereof comprises mechanism for use with an automatic bag bottom forming apparatus, the latter having a bag tube conveyor including, for example, spaced gripping means for consecutively gripping a plurality of bag tubes near opposite extremities thereof and moving same in succession relative to the apparatus in preselected spaced relationship along a com- 2,712,275 'Patented July 5, 1955 ICC end spreading means. The novel tube end spreading means (as opposed to a tube end opener) is also referred to as a bag bottom flap-forming device and comprises a plurality of improved spreader units which are movable in a novel manner upon a conveyor which, in cooperation with novel means, governs the attitude of each spreader unit relative to the path of movement of the bag tube. Each spreader unit is constituted by a pair of substantially L-shaped spreader arms, each of which are pivotally mounted upon the spreader unit conveyor with the so-called feet of the spreader arms, that is, the base of the L-shaped portions directed away from one another in opposite directions. The two spreader arms of each spreader unit are mounted relatively close to one another, the arms being pivoted to the conveyor at or near the upper or outer extremity of the body portions as opposed to the feet portions thereof. The spreader unit conveyor preferably is constituted by sprocket chain means which pass over suitable sprocket wheel means. The attitude of the spreader arms of each pair as they move through one complete cycle is controlled by grooved cam or guide means in which move followers which are connected to the L-shaped spreader arms. The spreader unit conveyor imparts a forward or linear movement to the spreader arms of each unit which moves same along linearly with and at the same speed of the bag tubes. Contemporaneous with ksuch forward or linear movement means are provided for angularly shifting the spreader arms about the pivots thereof in opposite directions away from one another whereby spreader fingers at the extremities of the spreader arms are brought into engagement with the end corners of the bag tubes thereby causing the end 'liaps to fold thereover and thereby forming the corner flaps and the corner folds in the tube ends. The spreader fingers are normally in a retracted condition and capable of entering a tube end despite a narrow separation of the sides thereof. Also the spreader arms are consecutively inserted into a partially open tube end in a region substantially beneath the axis of a sprocket wheel means. The grooved cam means w which controls the attitude of the spreader arms move such L-shaped arms to a position such that the spreaderpoints thereof are relatively close to one another during the insertion thereof into an open tube end thereby facilitatingl such insertion .despite a small dimension between: the folded side edges of the bag tube. Thus the means.

'for' controlling the movement of the spreader `units causes each arm ofa unit to be inserted separately into an open tube end shortly after the opening action ofa preliminary opening device, such vas that shown in my .aforementioned copending patent application. After such insertion of the arms of a spreader unit, the latter is mon path, the improved elements including improved tube moved along with the .moving tube end in linear or trans-` lational movement and the novel flap-forming or iiapfolding mechanism is actuated first by urging the extremities of the arms simultaneously against the opposite corners (side edges) of the tube end; and second by angularly separating the spreader fingers at the extremity of each of the arms to engage the opposite corners of the folded bag tube thereby to force an expansion of suchnormally retracted spreader fingers. Thus the end flaps of the bag tube are caused .to fold over each of the `pairs of such spreader fingers to form positively the cornerV and side flaps and the corner folds of the tube end.f Thereafter the spreader arms are consecutively removed from the bag tube end Without interfering with the folds which have been just formed, adhesive is applied to the aps andthe bag bottom is formed by folding the iiaps as will appear below. Y

Various, further and more specific objects, features and advantages of the invention will clearly appear from the detailed description given below taken in connection with the accompanying drawings which form a part of this specification and illustrate, by way of example, preferred arrangements of apparatus for carrying out the invention. rPhe invention consists in such novel combinations of features and method steps as may be shown and described in connection with the apparatus herein disclosed.

In the drawings:

Figs. l and la are respectively the first and second halves of an automatic bag bottom forming apparatus which is analogous to that disclosed in my copending application Serial No. 189,271, tiled October 9, 1950, now Patent No. 2,641,167, with the exception that the tube end spreader means embody improvements which, acting alone and acting in combination with the other elements, comprise the present invention;

Figs. Ztl-2j, inclusive, illustrate the successive steps in the formation of a pasted bag bottom by means of the present invention;

Fig. 3 is a side elevation, partly in section and with parts broken away, of portions of the novel tube end spreading means employed in the present invention, certain of the spreader units being omitted for clarity.

Fig. 3a is a side elevation of the device illustrated in Fig. 3 but showing all of the spreader units employed in this embodiment, thereby indicating the relative positions of the arms of all of such units at a given instant;

Fig. 4 is an end view, with parts omitted for clarity, of the apparatus shown in Fig. 3

Fig. 5 is a view of a portion of Fig. 3 but on an enlarged scale showing in greater detail the construction of a spreader unit and its action upon a tube end;

Fig. 6 is a plan view of an extremity of a spreader arm showing the spreader fingers thereof which are in retracted condition in position immediately prior to the spreading of an end corner of a bag tube;

Fig. 7 is a sectional view taken substantially on line 6-6 of Fig. 6;

Fig. 8 is a plan view of the extremity of a spreader arm showing the spreader` fingers thereof in extended condition;

Fig. 9 is a sectional view taken on line 9 9 of Fig. 8; and

Fig. 10 is a sectional view taken on line 10--10 of Fig. 8.

The form of the invention illustrated in the accompanying drawings, by way of example, comprises apparatus for operating upon the ends of a previously formed bag tube, or a succession of such tubes, preferably of the multi-wall stepped end variety, whereby automatically the bag tube end is opened and thereafter corner and end aps are formed thereon and the tube end is prepared to be closed and sealed with the exception of a bag valve, if

they can be adjusted as desired while the apparatus is in operation. K

The bag tube grippers 21 and 22 (Fig. 2a) are mounted upon a pair of synchronously driven endless sprocket chains or belts 24 and 25, respectively, and are adapted to grasp, together with the aid of numerous other similar pairs of grippers, bag tubes and to pull same in succession through the machine. The bag tube grippers act in pairs, one gripper of each pair being mounted upon each sprocket chain of the bag tube conveyor. Each pair of grippers is automatically closed simultaneously to grip a bag tube and the tubes are consecutively and automatically advanced to the grippers by means of a suitable feeder mechanism (not shown). After each bag tube has been pulled through the apparatus and a bag bottom is formed thereupon, the grippers are automatically and successively opened and the completed bags delivered therefrom consecutively.

Referring now to Figs. l and la, the novel apparatus is constituted by a main frame 26 upon which are mounted the various operating units and said bag conveyor means. The latter, as aforementioned, comprise the pair of endless sprocket chains 24 and 25 (Fig. 2a) which are respectively in engagement with suitable pairs of sprocket wheels (not shown) over which they are stretched. The path of the conveyors 24 and 25 is shown in side elevation in Fig. 1 schematically by a broken line 27 which also indicates in general the path of the bag tubes as they are drawn through thervarious operating units of the apparatus.

A bag tube, as at 28 (Fig. 2), having been grasped by the grippers 21 and 22, preferably has the ends thereof slit, as at 29, by a suitable slitting device (not shown). Thereafter the bag tube is scored near the extremities thereof, as at 30,`by means of a suitable scoring unit, indicated generally at31 (Fig. l). I have found it advantageous thereafter to bend the tube ends, as at 28a and 28b, about such score lines through preferably about 90 each to a position which is substantially perpendicular to the main body of the bag tube, that is, to a position as illustrated in Fig. 2c whereupon the bag tube is prepared for the action of a tube end opener and a tube end spreader. The latter is eiective to form the side and Y corner flaps upon the tube end, as above explained. How` any. Of course, if desired, one or both ends of a bag i tube can be formed into a bottom with or without a valve.

Referring to the drawings in greater detail, the novel elements described herein are designed for use with a continuously driven bag tube conveyor. The present invention employs, in combination with the above-men- "Il tioned elements for acting upon the tube ends, a master bag tube conveying means having a plurality of equally spaced bag tube gripping devices thereon by which bag tubes may be successively grasped and continuously advanced to the various operating stations at a uniform but Y adjustable speed. In Fig. 2, a pair of such gripping devices is shown at 21 and 22 which are designed for grasping the leading edge of a bag tube and urging it in the direction of the arrow 23 to such various operating stations. A common power source is employed for driving not only the bag tube conveyor but also the various units which act upon the bag tube and in particular the improved elements to be set forth herebelow. Suitable means are provided, however, for altering the phase adjustments of the novel elements for spreading the tube ends, together with certain of the other units, whereby ever, the invention is not limited to means for so bending the tube end nor to operation upon a bag tube which has had the ends thereof bentto such a position as shown in Fig. 2c, it being possible for the novel elements satis- I factorily to act upon tube ends which are in the same plane with the main tube body.

' As shown in Figs. 1 3a, 4 and 5, l have found it desirable to employ aV hold-down strap 21a which is secured to the frame 26, as at 22a, and beneath which the bags are moved by the conveyor means 24, 25.

Tube `emi openen-Means, as aforementioned, are provided for opening the bag tube ends, which means in general are constituted by a suction device which, for example, is designed to travel linearly with a conveyed bag tube thereby to gain a positive grasp on the opposite sides of the end of the bag tube, to open it and thereafter release it after at least a portion of a tube end spreader unit, to be described more fully hereinafter, has entered the open tube end to perform the operation of forming the corner and side flaps. Such a tube end opener can be similar to that shown in my aforementioned copending patent application Serial No. 189,271, or, if desired, a tube end opener can be employed similar to that shown in copending United States Patent 2,570,047, filed September ll, 1948, for Bag Bottomer by Edwin E. Burroughs.

Tube end spreader means.-The tube end spreader means, in the form shown, generally are divided into:

(a) A group of tube end spreader units each comprising a pair of substantially Lfshaped spreader arms having spreader fingers at the extremities thereof, one of which units lis shown generally` at 32 (Fig. 3);

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(b) Conveyor means for such tube end spreader units, such means being indicated generally at 33 (Figs. '3, 3a and 4);

(c) Attitude control means for the spreader arms comprising:

(l) A so-called primary guide device, indicated generally at 34;

(2) A secondary guide, indicated generally at 35; and

(3) Means for moving the primary guide device 34 relative to the lower run of the chain conveyor 33, such means being generally indicated at 36 (Figs. 3, 3a and 5).

The latter means 36 are further described as follows: The spreader unit 32 includes arms 32a and 32h which are pivotally secured to the conveyor means 33, as is well shown in Fig. 4. In order to accommodate bag tubes of differing widths, the pivotal connection of one of such spreader arms, as 32a, with the conveyor means 33 can be moved toward or away from the analogous pivotal connection of the other spreader arm. Such adjustment, of course, necessitates disconnecting such pivotal connection and re-connecting it at a differentlocation. The conveyor means 33 comprises, in the form shown, a pair of parallel side by side endless sprocket chains of equal length 33o and 3315. Chain 331i is visible in Figs. 3 and 3av and i's in engagement with a pair of sprocket wheels 37a and 37b which are rotatable respectively upon shafts 38 a-nd 39. The primary guide device 34 in effect constitutes a grooved cam which influences the positions of the arms 32a and 32h through the intermediaries of follower arms 40 and 4l, respectively, which are rigidly secured tosuch spreader arms and which have associated with the respective extremities thereof followers 42 and 43. The ,primary guide 34 is constituted by a horizontal straight center portion 34a having associated with the opposite extremities thereof a pair of inclined portions 34h and 34C, respectively, the formerbeing inclined downwardly toward such center portion 34u and the latter being inclined upwardly therefrom. it will be seen that when the follower rollers 42 and 43 are following the `center portion 34a, the spreader arms 32a and 32b can be .shifted simultaneously angularly either toward or away from one another by moving the center guide portion 34a (while horizontal) up or down relative to the bag tube `path 27 or toward or away from the conveyor means 33. The component chains 33a, 33.5 slide respectively between pairs of chain guides to be described below which provide proper support therefor .to facilitate suchV .angular movement of arms 32a, 32b. Thus the aforementioned means 36 for moving the primary guide 34 relative to the conveyor 33 (that is, up or down relative to the bag Stube path 27') thereby angularly shifts said spreader arms 32a and 32b, such means being operable simultaneously with translational or linear movement of the conveyor means 33. Thus there is imparted to the spreader unit. 32 :translational movement along with a bag tube and simultaneously angular movement thereby to separate the spreader arms to fold the open bag tube ends in such a manner positively to form the corner` and side v'flaps of the bag bottom.

The arms 32a and 321'), as shown in Fig. 3, are preferably L-shaped. The upper extremity, `i.`e., the shank or body portion of each of the L-shaped spreader arms is pivoted to the conveyor means 33, as aforementioned, and the foot portion of the L-shaped arms, as opposed to the shank thereof, is constructed and arranged to enter into the end of the bag tube. The invention, 'of course, is not limited to the employement of a ba'gshaping spread'- er arm of .precisely L-shape and this term isintended to embrace members which can be pivotally mounted as aforementioned and which are provided with a foot portion substantially similar to that shown i Further regarding the conveyor means 33, reference is made to Fig. 4 wherein the sprocket conveyor chains 33a and 33b are shown in both the upper and lower-runs thereof, each held between suitable chain= guides which prevent sagging thereof or motion in a vertical plane. For example, the sprocket chain 33a in the lower mn thereof is held between chain guides 45 and 46 and in the upper run thereof between chain guides 47 and 48. The upper and lower runs of the chain 33b move respectively between cha-in guides 49, St) and 51, 52. Said chain guides are rigidly secured to suitable brackets, as at 53, which are mounted upon the stationary framework of the apparatus.

The pivotal association of all of the units 32 with conveyor means 33 is as follows: each of the spreader arms 32a and 32h thereof yis pivotally mounted upon a pivot pin, as at 54 (Fig. 4), which is secured at its `extremities to the conveyor chains 33a, 33h. Such chains are moved in phase and at a common speed. That is, there are two sprocket wheels (one of which is shown at 37a, Figs. 3, 3a) keyed to the common shaft 38 and respectively engaging the chains 32a and 32b. Similarly f there are two sprocket wheels (one of which is shown at 37b) which are keyed to the shaft 39.

Shown in section in Fig. 4 is the center portion 34a of the primary guide 34 showing the follower 42 of the arm 40 which in turn is secured to the spreader arm 32a. The center portion 34a of guide 34 is positioned in Fig. 4 forproducing the maximum angular separation of the spreader arms 32a and 32b.

The opposite eXtrem-ities of the pin 54 may be secured to the chains 33a, 33b, respectively by pivotal connectors. For example, suitable pins 55 and 56 respectively so connect the opposite ends of the pin 54 to bifurcated members 57 and 58, which members a're rigidly secured to said chains 33a, 331;, respectively.

As shown in Fig. 3a, there may be, for example, :live spreader units, that is tive pairs of spreader arms, as at 32a, 32h, mounted upon the spreader unit conveyor means 33.

. The aforementioned secondary guide 35 is constituted by arcuate end portions 35a' and 35h respectively associated with the sprocket wheels mounted upon the shafts 38 and 39. That is, arcuate guide portion 35a is associated with the pair of sprocket wheels mounted on shaft 3S, .and arcuate guide portion 35b with ythe two sprocket wheels mounted on shaft 39. The upper extremities of such arcuate ,guide portions are interconnected by means of a center guide portion 35e which runs parallel to the upper -run of ythe conveyor chains 33a, 33b. The guides 35a, 35b and 35e comprise grooved cams for engaging suitable followers for controlling the angular positions of the spreader arms 32a, .32b as follows: Each of the spreader arms 32u, 32b .has an additional follower arm rigidly secured thereto as at 5.9 land 60, respectively, lto the ends of which-vare respectively connected cam follower rollers 61 and 62. Each of these rollers is designed for entering a ared or bell portion 35b formed at the lower extremity of thearcuate guide portion 35b, such entrance beingeffected vbefore the other cam follower roller connected to the same arm has moved out of the primary guideV 34. lAs will appear more fully hereinafter, as the spreaderarm 32b moves to the right, as viewed in Fig. 3; the follower roller 43 will move into the upwardly inclined4 ,guide portion 35e and consequently the spreader ann 32h will be shifted angularly clockwise to `withdraw the extremity of the spreader rarm from Aa tube end and concurrently the follower 62 will move into the arcuate guide 35 thereafter causing arm 32`b 'to be further shifted in a clockwise direction to move the shank or body portion of the arm. substantially into a horizontal position, as in Fig'. 3a, by the time it reaches the upper run of the conveyor means 33. The other spreader arm 32a, under the inuence of the upwardly inclined guide portion 34e and the follower 42, will be shifted counterclockwise to withdraw same from a bag tube as it advances from left to right, Yas viewed in Fig. 3. Similarly the follower r61 willyengage the secondary guide 35 and arm 32a will :be

alnaav shifted further angularly in a counterclockwse direction to a position corresponding to that of spreader arm 32b.

Referring now to Figs. 6, 7 and 8, there will be described the retractile spreader linger unit, one of which is secured to each lower extremity of each spreader arm'. Such a unit is indicated generally in Fig. 6 at 63 which is shown in association with the outer extremity of the spreader arm B2b. p

The extremity of each spreader arm, as at 32b, is bifurcated thereby forming parallel members 32h and 32b Pivotally secured between such bifuracted extremity 'is a so-called spreader frame 64 upon which is mounted the spreader lingers aforementioned. Such spreader lingers are indicated at 65 and 66. The spreader frame'64 is pivotally mounted upon the spreader arm 32h by means of pivot pins 67 and 68. However, the angular movement of the spreader frame 64 is yieldingly restrained within preselected narrow limits, for example, about 15, by means which are well shown` in. Fig. 6 comprising a stud member 69 having a conical tip which protrudes into a recess 70 formed in the rear extremity of the frame 64. The stud 69 is yieldingly held in the position shown in Fig. 6 by means of a spring 71 thereby forcing the stud 69 against suitable limit-stops 69a which prevent further movement to the right, as viewed in Fig. 6. The stud 69 does not protrude to the bottom of the recess 70 but is only partially inserted therein. Consequently the spreader frame 64 can shift angularly between the position shown in solid lines in Fig. 7 and that shown in broken lines. l

In order to provide a spreader linger device for the extremity of each spreader arm, which device normally will be in a retracted condition but which will spread in response to pressure against the end or corner of an open tube end, there is mounted upon the spreader frame 64 a spreader point member or spreader tip member, shown at 72, which in turn is associated with the frame member by means of a plunger 73 which is shiftable axially relative to the frame member 64 in a suitable bore -therein. The axis of such plunger 73 preferably is parallel to and caplanar with the plane of angular motion of the spreader arm 32h. A collar 74 is secured to the rear extremity of the plunger 73 and the spreader tip member 72 is urged resiliently away from the spreader frame 64 by means of a coil spring 75.

The aforementioned spreader lingers 65 and 66 are, each at one extremity thereof, pivotally secured to the spreader tip member 72, as at 65a and 65D. lAlso said spreader lingers 65 and 66 are operatively associated with the spreader frame 64 by means of links 76 and 77, respectively, each of which is pivotally associated with said frame and its respective spreader linger. The links 76 and 77 are secured to the lingers 65 and 66 in such a manner that such fingers are in their retracted position when the coil spring is extended to its maximum length 5' permitted by the collar 74 engaging a limit-stop 64a. Thus when the spreader linger device is inserted into an open tube end and the tip 72 engages the corner thereof, as shown in Fig. 6, the lingers will be initially retracted, as shown, but continued pressure upon the spreader arm 32h will force the spreader frame 64 to the right, as viewed in this figure, thereby to overcome the pressure of the spring 75 and to spread the lingers 65, 66 to the position as shown in Fig. 8, thereby to form the corner and side flaps for the bag bottom, as shown in Figs. 2f and 8.

The spring 71 will yieldingly hold the spreader frame 64 in a desired position for so forming the corner and side flaps of the bag bottom. However, said frame will be released from restraint by the stud 69 when some excessive and undesired force is exerted upon the frame 64 and acting about the axes of the pivot pins 67, 68.V

Referring now to Figs. 3 and 5, there will be described the means for simultaneously angularly moving the spreader arms, as at 32a, 32h, while the same are undergoing linear or translational movement along with a bag tube. The primary guide means 34, as above set forth, comprises a center portion 34a and portions 34b and 34e which are respectively secured to the entrance and exit extremities of portion 34:1. The extremities of the guide 34' are mounted for both pivotal and linear movement. For example, the lefthand extremity of the guide portion 34b is provided with a stud 78 which engages a horizontal slot 79 formed in a bracket 80 secured to a stationary portion of the apparatus frame. Analogous means are provided for the righthand extremity of the guide portion 34e. The length of the slot 79 is suflicient to permit substantial movement up or down of the center portion 34a. The latter, as is well shown in Fig. 5, is'pivotally supported at 81 and 82, respectively, upon bell crank arms 83 and 84 of bell cranks indicated generally at and 86, respectively. The arms 83 and 84 are substantially horizontal, and perpendicular thereto respectively are arms 87 and 88 lwhich are interconnected by a rod 89, the length of which can be adjusted byV a conventional turnbuckle 90. It is clear that the center guide portion 34a can be lifted or lowered by angularly moving together the bell cranks 85 and 86.

Suitable means are provided for lowering and raising such center guide portion 34a and simultaneously therewith angularly shifting the guide portions 34b and 34e about-the axes of their respective studs, as at 78, comprising, in the form shown, a pair of cams 91 and 92 which are keyed to a common shaft 93. The cam 91 engages a suitable follower 94 which, for example, is mounted at the upper extremity of the bell crank arm 88. When the follower 94 rides upon the high portion or plateau of the cam 91, it is seen that the center guide portion 34a will be lowered relative to the table 95 upon which the bag tubes move and hence moved parallel toward the lower run of the spreader unit conveyor means 33. This, of course, is accomplished through the linkage, including the bell cranks 85 and 86. Through the intermediary of the guide followers 42 and 43 and their follower arms 40 and 41, respectively, the spreader arms 32a and 32h are shifted angularly away from one another thereby to urge their respective spreader tips, as at 72, into the corners of the open tube ends. Engagement by such spreader tips with the tube end corners is simultaneous. The spring 75 (Fig. 6) is overcome and the spreader fingers 65 and 66 are extended from their retracted position (Fig. 6) to their extended position (Fig. 8) thereby quickly and positively to form the corner and side flaps for the bag bottom and to shape the opposite corners of the tube end.

Means are provided for positively returning the spreader arms to their initial or unspread condition prior to the withdrawal thereof entirely from the tube end. Such means' comprise a cam follower 95 which cooperates with the cam 92 and, by means of an arm 96, which is drivably connected to the bell crank 86 via its shaft, is capable of angularly shifting the latter crank in a direction to return the spreader arms 32a, 3212 to such initial unspread condition.

After the spreader arms 32a, 32h have been separated to their maximum extent within a tube end under the influence Aof the cam 91 whereby the side and corner flaps and the end corner fold lines are formed, each tube end is moved beneath a pair of supplementary or side flap guides 97, 98 shown in Figs. 2f and 4. The lower or bottom edge of such side ap guides 97 and 98 gradually approaches the table upon which the bag tubes move. The lower edge of each such supplementary or side liap guide is positioned preferably in the corner between an end llap and side flap, as is well shown in said Fig. 2f, and thereby holds the spread tube end in a desired position while the spreader arms are withdrawn entirely therefrom and the tube end is pressed, as will appear hereinafter.

Referring again to Figs. 1 and la, the tube end spreader is generally shown at 99. rthereafter the tube is acted upon by mechanism to complete the forming of the bag bottom, as mentioned in the United States copending application Serial No. 48,820, filed September l1, 1948 by Edwin E. Burroughs. That is, the tube ends are pressed as by pressing rollers indicated generally at 100 and thereafter the bottom fold or score lines are formed, as at 101 (Fig. 2g), by a scoring device 102. An adhesive is then applied, as shown in Figs. 2h and 2z by a suitable gluing device 103, a sleeve is inserted by suitable sleeving means 104, and thereafter the side flaps are folded over and pressed to complete the bag bottom, as shown in Fig. 2i.

A common driving means, such as an electric motor (not shown), provide torque for driving the entire apparatus and such motor may be operatively connected to a main power shaft 105 (Fig. l) which extends substantially the full length of the apparatus and is rotatably mounted upon one side of the frame 26 by means of suitable brackets, as at 106. Extending transversely across the path of the bag tubes is a so-called transverse power shaft 107 (Fig, l) which communicates power to the tube opening device employing the aforementioned suction cups. Torque from the main power shaft 105 is communicated to the shaft 107 by means of a gear train as follows: A gear 108 upon the shaft 105 meshes with a gear 109 upon an intermediate shaft 110. The latter, through suitable miter gears located within a housing 111, communicates torque to a vertical shaft 112 which is operatively connected to the aforementioned transverse shaft 107 also through miter gears located within a housing 113.

ln order to provide manually operable means for adjusting the phase relationship of the aforementioned suction cups with the bag tube-conveyor chains 24, 25 and hence with the bag tubes which are conveyed thereby, a manually adjustable differential 114 is interposed in the shaft` 110, such differential having an adjustment knob, as at 115, adjustment of which will effect the desiredphase adjustment of said cups with the oncoming bag tubes.

The movement of the tube end spreader units is, of course, synchronized with the movement of the bag tube conveyor chains 24, 25 whereby the spreader arms of such a unit are consecutively inserted into each open tube end in a desired phase relationship. Such phase relationship of the spreader units and the bag tube conz veyor chains can be adjusted by a hand adjustable differential in the torque power line for the pinions supporting the conveyor chains 33a, 33b. Such torque transmission lines includes a shaft 116 and 117 which are driven by shaft 105. Interposed in shaft 116 is a differential, as at 118, having an adjustment knob 119.

In operation, the phase relationship of the spreader unit conveyor means 33 is adjusted whereby a leading spreader arm, as at 32b, is lowered into the aperture of an open tube end thereby widening same, such aperture having been formed by the aforementioned tube end opener. The insertion of the tip of the tube end spreader 32b into such aperture is effected under the influence of the guide portion 34b and the arcuate guide portion 35a. After the roller 62 has emerged from the latter arcuate guide portion, the downwardly inclined primary guide portion 34b angularly shifts the spreader arm 32b gradually from a relatively elevatedposition into that shown in Fig. 3 wherein the spreader tip, as at 72, comes to a stop on the base line 30 of the tube end (Fig. 2b). The insertion of the first spreader arm 32b as aforementioned assists in widening somewhat the aperture of the tube end and thereby assists in opening the tube end suiciently to permit the second spreader arm 32a to enter i Ut and reach a symmetrical position. When the spreader arms have been so introduced into the open tube end, the rollers 42 and 43 have reached the center guide portion 34a and are moving in a rectilinear course therein. The cam 91, moving in timed relationship with the bag tube and spreader unit conveyors, lowers the center portion 34a temporarily thereby angularly shifting the spreader arms 32a, 32b about their respective pivots 53 in opposite directions to separate spreader tips 72 thereof. There is thereby brought about a gradual and uniform' pressure upon each spreader tip 72. The two spreader tips simultaneously engage an-d are restrained by the corners of the tube end thereby forcing outwardly into a spread condition the respective spreader lingers thereof. Thus the side and corner iiaps of the bag tube are formed, as shown in Figs. 2e and 2f. Thereafter the tube end is passed into engagement with the supplementary guides 97 and 98 which hold the tube en-d open for the succeeding phases of manufacture, as shown, for example, in Figs. 2g-2j, inclusive. The guide followers 42 and 43 thereafter are forced to ride upwardly in the primary guide portion 34e thereby consecutively angularly shifting the spreader arms 32b and 32a, respectively, in clockwise and counterclockwise directions, thereby consecutively angularly to shift same out of the tube end in a uniform and gradual manner. Thus the spreader arms 32b and 32a move out of the bag under the inuence of said rollers (43, 42 and 62, 61), executing a movement opposite to that performed when they were introduced into the tube end.

The extent of the pressure which can be exerted by the spreader fingers 65, 66 is adjustable by adjustment of the position of the guide 34 upon a suitable bracket (Fig. 4) by means of suitable conventional adjusting means, as shown generally at 121 and 122, Said bracket 120 is, of course, mounted upon a stationary Yportion of the frame.

While the invention has been described with respect to a preferred example which has given satisfactory results, it will be understood by those skilled lin the art, after understanding the invention, that various'changes and modifications may be made without .departingfrom the spirit and scope of the invention, and -it is intended therefore in the appended claims to cover all such changes and modifications. v

What is claimed as new and Letters Patent is:

l. In apparatus for forming the bag `bottom flaps of a bag tube including: a conveyor for a plurality of said bag tubes for moving same in succession along a common path; a spreader unit; a conveyor for said spreader unit for moving the latter linearly along the path of said bag tubes; said spreader unit comprising: a pair of L-shaped spreader arms pivotally secured to the conveyor therefor, each of such spreader arms having a foot portion, the latter having normally retracted but expansible spreader fingers pivotally secured to the extremities thereof; and means for simultaneously shifting said spreader arms angularly in equal and opposite directions contemporaneis desired to be secured by ous with such linear movement,4 thereby to move the ex-V tremities of such feet portions in opposite directions, such shifting means being operable in timed relationship to said bag tube conveyor whereby such feet portions are inserted within the end of such .bag tubes with such spreader lingers normally retracted, such shifting means spreading such arms angularly to a degree suiicient v-for said spreader fingers to engage opposite corners of such bag tube and to expand under the influence of further angular vmovement of such spreader arms.

2. In apparatus for forming the side and corner tiaps and shaping the open end of a bag tube comprising: a pair of spreader arms; a conveyor for said spreaderarms, the latter being pivotally secured to the former; a conveyor for such bag tubes for moving a plurality thereof in succession along a common path; a central guide member operatively associated with said spreader unit for controlling the angular position of said spreader arms relative to the path of said bag tubes, said central guide member including a first branch inclined downwardly relative to said. bag tube path, a second branch substantially parallel to said bag tube path, and a third branch inclined upwardly from such path, a pair of follower arms secured to respective of said spreader arms for engaging said guide, said first and third branches of said guide acting respectively successively to shift angularly said spreader arms into the partially open end of a bag tube and successively to shift said arms outwardly thereof; means for moving said central branch of said guide substantially parallel to the path of said bag tubes away from and toward such path thereby angularly to shift said spreader arms in opposite directions; and a pair of normally retracted spreader fingers secured to each of said spreader arms.

3. In apparatus for shaping the end corner folds of bag tubes comprising; a pair of L-shaped spreader arms mounted in alignment with one another for angular movement in a substantially common plane; a pair of normally retracted but expansible spreader fingers secured to each extremity of the spreader arms, such extremities being directed in opposite directions; and means for simultaneously moving said spreader arms linearly and angularly, such angular movement thereof shifting said spreader arms in opposite directions within a single tube end for expanding such fingers at opposite corners of such tube end thereby forming such folds.

4. In apparatus for shaping the ends of bag tubes, a conveyor for moving such tubes successively along a common path; means for partially opening such tube ends successively; Vand tube end spreader means for acting upon such opened tube ends including: a spreader unit, the latter comprising a pair of endless chains mounted par allel and side by side; a pair of spreader arms pivotally secured between said chains, means for moving said chains together and at a common speed, said chains being movable in planes which substantially parallel the direction of movement of said conveyor, each of said spreader arms having a spreader frame secured thereto, a spreader tip plunger mounted for axial movement relative to said frame, a spreader tip member secured to such plunger at the latters outer extremity, resilient means for urging said frame and tip member apart, a pair of spreader fingers pivotally secured to said tip member and normally in a retracted position, each of said lingers being linked to said frame whereby movement of said frame toward said tip member will spread said fingers; and means for automatically and cyclically pivoting said arms in opposite directions simultaneously through preselected angular increments for urging said tip members against opposed end walls of successive of said bag tubes.

5. In apparatus for shaping the ends of bag tubes, the combination comprising: a pair of spreader arms; a conveyor for mounting such arms; each of said arms having secured to the outer extremity thereof: a plunger mounted for axial movement relative to such extremity, a spreader tip member secured to such plunger for engaging the inner corner of a tube end, a pair of spreader fingers pivotally mounted upon said tip member and associated with said arm extremity for spreading movement responsive to movement of said arm extremity and tip member toward one another, said tip members on each pair of arms being pointed in opposite directions, means for resiliently urging said arm extremity and tip member apart; and means for automatically and cyclically pivoting said arms in opposite directions simultaneous with the movement of said conveyor therefor.

6.' In apparatus for shaping the ends of bag tubes, a tube conveyor for moving such tubes successively along a common path; a spreader unit; a spreader unit conveyor for moving such spreader unit along the same path as said tubes, such unit comprising: a pair of spreader arms each pivotally secured to said conveyor, each of such arms mountingat the extremity thereof a tip member, a pair of spreader iingers pivotally secured to each of such tip members, means for normally holding such fingers in a retracted position, means for spreading each pair of said fingers in response to relative movement of its respective tip member and arm; and means for simultaneously shifting said arms angularly in opposite directions contemporaneous with movement thereof by said spreader unit conveyor.

7. ln apparatus for shaping the ends of bag tubes, the combination comprising: a tube-conveyor for moving such tubes successively along a common path; a spreaderunit comprising: a pair of spreader arms each pivotally secured to a mounting therefor, a spreader point member, a pair of spreader fingers pivotally secured to such spreader point member, one of the latter being mounted upon each extremity of said spreader arms, means for normally holding said spreader fingers in a retracted position, said fingers being spreadable in response to relative movement of said spreader point member and arm; a conveyor for said spreader arm mounting for moving said spreader unit along the path of tubes moved by said tube conveyor; and means for angularly shifting saidspreader arms in opposite directions whereby said spreader point members en-v gage the opposite corners of s'aid tubes, said spreader fingers being spreadable in response to said members so engaging the corners of said tube ends and being urged thereagainst.

8. ln a bag tube end spreader device, a spreader unit comprising a pairrof angularly shiftable spreader arms, a spreader point member axially shiftable uponthe extremity of each of said arms, a pair of spreader fingers pivotally secured to each of said spreader point members and operatively associated with the respective spreader arm thereof; resilient means for urging said spreader point member away from said spreader arm whereby said spreader fingers are resiliently maintained in a retracted position; a spreader unit conveyor for moving such unit linearly; and means for angularly shifting simultaneously said spreader arms in opposite angular directions during a preselected portion of its linear movement whereby said spreader point members are separated, caused to engage opposite end corners-of a bag tube end thereby to produce relative movement between such member and arm to spread such spreader iingers and thus to form the side and corner flaps of such bag tube end.

9. lnapparatus ofthe class described, a conveyor for conveying a plurality of bag tubes successively along a common path; a pluralityI of spreader units; an endless conveyor for said spreader units for moving same over a portionof the-run thereof along a path adjacent to the path of said bag tubes; each of said spreader units including: a pair of spreader arms pivotally secured tov said end less conveyor, a pair of normally retracted spreader fingers secured to the extremity of each of said spreader arms;

and means for angularly shifting said pivotally mounted arms in equal amounts in opposite directions contemporaneously with translational movement by said endless conveyor. t

' l0. In apparatus of the class described, a conveyor for moving bag urbes in succession relative to said apparatus and along a common path; a spreader unit', a conveyor for said spreader unit formoving same along a path parallel to and adjacent the path of said bag tubes, said spreader unit comprising: a pair of L-.shaped spreader arms pivotally secured to said spreader unit conveyor, said spreader arms having the outer extremities thereof pointed in opposite directions; a pair of spreader lingers secured to each such extremity of said spreader arms, resilient means for normally holding said fingers in a retracted condition, cam means for successively shifting said spreader arms angularly thereby to insert the extremities thereof arms and to urge said spreader fingers against the corners of said tube ends.

References Cited in tlie file of this patent UNITED STATES PATENTS Cline Sept. 1, 1891 

